A teenager has been left needing surgery after being stabbed repeatedly in a takeaway by masked assailants.
Footage of the stabbing in Brixton, south London, has been released by Scotland Yard detectives in a bid to trace the 18-year-old's attackers.
Clad in black and armed with knives and belts, the clip shows at least three men whipping, punching and kicking several apparently defenceless victims.
The teenager, who has not been identified, was hit in the face with a belt then stabbed several times by one of the suspects, Scotland Yard said.
When he fell to the floor one of the suspects stabbed him again before kicking him in the head.
The teenager suffered four stab wounds to his leg, one to the abdomen and one to the arm in the attack that took place on Monday evening.
Police said they were called to the Dallas Chicken takeaway on Brixton Road at 5.30pm.
The victim was rushed to hospital in south London and underwent surgery on his abdomen. He has since been discharged but requires further surgery to the wound on his arm.
Detective Constable Remy Smith, from Lambeth CID, said: "This is a shocking and brutal assault that has left the victim very distressed from his ordeal. We are keen to identify the men in the CCTV footage so we can speak to them about the incident. We would also urge anyone who witnessed the incident to contact us."
According to witnesses there were a further three suspects on bicycles outside the shop at the time of the assault. All of the suspects then left together as a group as they made their way northbound along Brixton Road.
One man was later arrested on suspicion of possession of a knife and police appealed for help in finding four other suspects.
One is described as a black man, aged in his early 20s, of medium build. He was wearing a black puffa-style jacket, blue jeans, a white belt, a black face-covering and black shoes with white laces.
A second is described as a black man, aged in his early 20s. He was wearing a black jacket, dark trousers, a black face-covering and black shoes. He was seen carrying two knives.
A third is described as a slim black man, aged in his early 20s. He was wearing a black jacket, dark trousers, black gloves, a black face-covering and black shoes. He was seen to carry a knife.
A fourth is described as a slim black man, aged in his early 20s. He was wearing a black jacket, dark trousers, black gloves, a black face-covering and black shoes.
Anyone with information or any witnesses are urged to call police via 101 or on Twitter via Metcc or Crimestoppers anonymously on 0800 555 111.